For emerging applications such as wireless domestic networks, smart networks or similar networks, the use of directive antennas, namely antennas with the faculty of focussing the radiated power in a particular direction of space, proves to be particularly attractive. Indeed, the use of directive antennas can reduce the power of transmitters and significantly limit interferences, the reduction in power of the transmitters is translated by a reduction of costs of equipment and/or increase in the lifetime of batteries and hence the autonomy of mobile equipment or wireless sensors.
However, the laws of physics require a minimum size for antennas, this size being all the greater as the antenna is directive or its operating frequency low. Hence, until now, the use of directive antennas has remained limited to antennas operating at very high frequencies, often at fixed frequencies, and not having size constraints such as radar applications or satellite applications.
However, to increase the capacity and bitrates of wireless systems, the emerging applications such as MIMO systems (for Multiple Input Multiple Output) use multiple antenna techniques. Hence, the grouping of directive antennas into networks is sometimes necessary to ensure point to point coverage in the entire space or on 360°. Moreover, to these more or less agile semi-directive antenna devices, a digital processing unit must be added to control and shape the beams in the directions required by the system. Indeed, the basic principle of a multibeam antenna system lies in the choice of one beam among a row of diverse fixed beams pointing in prioritised and predefined directions. The switching from one beam to another is decided according to, for example, the highest signal-to-noise ratio at reception.
Hence, in terms of integrated function within a multibeam antenna system, this must comprise a beam shaper that generates multiple beams, a listening circuit that is used for determining the beam to use to enable the optimal communication and a switch that is used to select the optimal beam for the reception. Therefore, the solutions currently on the market are complex solutions and, consequently, costly and/or bulky.